1. Field of the Invention
The present invention relates to an electron emission device, and an electron emission display including the electron emission device.
2. Description of the Related Art
Generally, an electron emission device is classified as either a hot cathode type and a cold cathode type, wherein the hot cathode type and the cold cathode type employ a hot cathode and a cold cathode as an electron emission source respectively. A cold cathode type electron emission device comprises a structure such as a Field Emitter Array (FEA), a Surface Conduction Emitter (SCE), a Metal Insulating Layer Metal (MIM), a Metal Insulating Layer Semiconductor (MIS), and Ballistic Electron Surface Emitting (BSE).
The foregoing electron emission devices are employed for an electron emission display, various backlighting, and a lithography electron beam. Among these, the electron emission display comprises an electron emission substrate provided with the electron emission device to emit electrons, and an image display substrate in which the emitted electrons collide with a fluorescent material to emit light. Generally, the electron emission display comprises: a plurality of electron emission devices formed on a first substrate, driving electrodes to control the electron emission of electron emission devices, a fluorescent layer formed on a second substrate and colliding with the electrons emitted from the first substrate, and a focusing electrode to accelerate the electrons toward the fluorescent layer.
In the electron emission display, while the electrons are emitted, an arc can be generated due to a high voltage within an internal space limited by an anode substrate and a cathode substrate. Here, the anode substrate corresponds to the electron emission substrate and the cathode substrate corresponds to the image display substrate. The higher the voltage applied to the anode electrode, the greater the probability that an arc is likely to be generated. In more detail, when a voltage of 1 kV or more is applied to the anode electrode, an arc is likely to be generated. In the structure in which the cathode substrate and the anode substrate are coupled with a spacer, it is difficult to maintain a level of brightness in a stable manner. The arc generation causes the electrodes formed as a thin film to be damaged, thereby deteriorating stability. Besides, a gate electrode, a cathode electrode or a metal mesh can include a protrusion and foreign material, which causes an electric field to be non-uniform, thereby causing abnormal light-emission and arcing. Accordingly, there has been proposed an electron emission display comprising an electron emission device having an improved structure capable of preventing arcing due to the high voltage.
An example of an electron emission display having an arcing prevention structure is discussed in Korean Patent First Publication No. 2001-0081496.
Such an electron emission display comprises a first substrate, a second substrate, and a spacer provided between the first and second substrates to maintain a constant distance therebetween. A cathode electrode having a stripe shape, a dielectric layer, and a gate electrode having a stripe shape situated transversely to the cathode electrode are formed in sequence on the second substrate. A micro tip is formed on the cathode electrode as an electron emitter. An anode electrode having a stripe shape situated transversely to the cathode electrode is formed on a first substrate opposed to the second substrate. A fluorescent layer facing the second substrate is formed on the anode electrode. A grid electrode is formed between the gate electrode and the anode electrode to control the electrons emitted from the micro tip.
With such a configuration, even though a high voltage is applied, the electric field applied to the gate electrode is not high, so that arcing is substantially prevented and an anode voltage is prevented from being partially applied to the cathode electrode.
However, in such an electron emission display having the foregoing configuration, the grid electrode is employed as an optional element for focusing the electrons and intercepting the electric field. Therefore, an additional process is needed to form the grid electrode. Furthermore, the protrusion and the foreign material of the grid electrode cause the electric field to be non-uniform, so that problems such as abnormal light-emission and arcing still arise.